hi Mr. Mile
i've build your AX17S, it work nice...sound is comparable with my GC even i only use standar componet. This is my first Solide State i've ever build.
I use +-44 volt DC.
there are few question i want to ask:
1. how to set bias? i've measured 0R33 and can't get fix value, is this normal?
2. my dc offset is about 34mv is this normal too?

Set 15mV across 0,33R for 50mA bias. PN voltage is 550mV like zener voltage, and you can't set bias with measure Vbe multiplayer voltage, and for TEF it's will be about 3,2V for any bias current. With 2,4V on Vbe multiplayer amp work in class B.
Regards

Dear Mr. Mile,
i measured voltage across 0,33R without load i get 0mV, and with load i get about 3-15mv up and down.

"...and for TEF it's will be about 3,2V for any bias current"... how to measured this?

Dear Mr. Mile,
i measured voltage across 0,33R without load i get 0mV, and with load i get about 3-15mv up and down.

"...and for TEF it's will be about 3,2V for any bias current"... how to measured this?

thanks and regards
naf

Replace R21 (1k) with 1,2k or 1,5k and you can set 15mV across 0,33R.
Offset must be 1mV with DC servo. You can test amp without DC servo just remove R36 (1k) and add 220uF in series with R15 (22R),
Regards

Replace R21 (1k) with 1,2k or 1,5k and you can set 15mV across 0,33R.
Offset must be 1mV with DC servo. You can test amp without DC servo just remove R36 (1k) and add 220uF in series with R15 (22R),
Regards

Gentlemen, I have a problem. 14.38 VDC output and do not know what is. I repalece BC547 - BC546B, BC557 - BC556B, 2N5401 - BC556B reverse, BD139 - MJE340. Instead 0,33R i put 0,22R. P1 set 10mV on 0,22R, all transistors tested and look good, any idea what is wrong?

Gentlemen, I have a problem. 14.38 VDC output and do not know what is. I repalece BC547 - BC546B, BC557 - BC556B, 2N5401 - BC556B reverse, BD139 - MJE340. Instead 0,33R i put 0,22R. P1 set 10mV on 0,22R, all transistors tested and look good, any idea what is wrong?

You must connect input gnd to psu gnd for test, many people made same mistake.
Can you post pictures?
Regards

Haha thanks Apex, now work i must remember for the future... Bias is 10mV . DC output is ~ 1mV. I have a little weak trafo, only 2x45VDC and drops to 2x40VDC under load. Next be made HV350, and I think it enough for me AX14 will be to the subwoofer, work with HL2. I'm interested in class "H" I've never heard of such an amplifier.
Anyway, thanks for the diagrams... And i'm thinks AX14 is good for home audio for normal people hehe.